My Son Who Is Now 16 Had His Gall Bladder

my son who is now 16 had his gall bladder removed a little over a year ago, is having constant stomach pain again. His medical history has included constant constipation since he was a baby. He has also had his appendix removed when he was 9 years old. I am concerned that maybe he has a digestive disorder or immune deficiency disorder. Are there conditions that could lead to chronic constipation and an over exertion of the appendix and gall bladder that causes need for removal at this early stage in life?